.learn-content {
    position: relative;
    /* background-color: greenyellow; */
    opacity: 0.8;
    z-index: 7;
}

/* 顶端目录*/
.head-Navigation {
    position: relative;
    /* top: 30px; */
    height: 34px;
    background-color: #B0E2FF;
}

.head-menu {
    padding-left: 300px;
}

.head-menu li {
    float: left;
    line-height: 34px;
    padding: 0 20px;
}

.head-menu li a {
    color: white;
}

/* 左侧目录 */
.left-Navigation {
    position: relative;
    width: 96px;
    left: 160px;
    top: 30px;
    float: left;
    border-radius: 5px;
    border: 1px solid #D3D3D3;
    background-color: #fff;
    box-shadow: 2px 2px 10px #909090;
}

.left-Navigation p {
    text-align: center;
    color: #777;
    cursor: not-allowed;
    background-color: #eee;
    padding: 5px;
    border-left: 5px solid #009E94;
}

.detail-left-menu {
    list-style: none;
    text-align: center;
    margin-right: -1px;
}

.detail-left-menu ul {
    padding-top: 20px;
}

.detail-left-menu li {
    /* padding: 5px 0 5px 0; */
    line-height: 30px;
    cursor: pointer;
    padding-top: 1px;
}

.detail-left-menu li a {
    display: block;
    /* color: #000000; */
}

.detail-left-menu li a:hover {
    background-color: #87CEFA;
    color: #fff;
}

.active {
    background-color: #87CEFA;
    color: #fff;
}

/* 中间内容 */
.learn-main {
    position: relative;
    border-radius: 5px 5px 0 0;
    top: 30px;
    left: 12%;
    width: 1050px;
    min-height: 600px;
    float: left;
    opacity: 0.8;
    background-color: white;
    box-shadow: 2px 2px 10px #909090;
}

.change-title {
    height: 30px;
    background-color: #EEEEEE;
}

.change-title span {
    line-height: 30px;
    font-size: 16px;
    cursor: pointer;
}

#pre {
    float: left;
    padding-left: 20px;
    display: none;
}

#next {
    float: right;
    padding-right: 20px;
}

/* 返回顶部 */
#totop {
    position: fixed;
    top: 600px;
    right: 80px;
    padding: 5px;
    background-color: white;
    box-shadow: 2px 2px 10px #909090;
    border: 1px solid #E0E0E0;
}

#totop i {
    font-size: 30px;
    color: #AAAAAA;
    cursor: pointer;
}

#totop i:hover {
    color: #FF0000;
}

/* 正文 */
.learn-text {
    padding: 20px;
}

.learn-text h3 {
    font-size: 24px;
    font-weight: bold;
    padding-bottom: 10px;
    border-bottom: 1px solid #9FB6CD;
}